This patch creates a fullfills? function within MaserDeviceInstance. It just calls the corresponding fullfills? function of it's member device_model.

I allows operations like my_device_dev.fullfills? Services::MyService as when working with InstanceRequirements or Compositions etc.. Thus it creates more consitency.
Fullfills? function for MasterDeviceInstance
Merge branch 'misc' of github.com:/maltewi/tools-syskit into misc